1. Annex 6 to Convention on international civil aviation organization (2016) Operation of aircraft. Part I. International commercial air transport. Aeroplanes. Tenth edition. Montreal: ICAO. ISBN 978-92-9249-971-6. p 64. p 4.3.5. Meteorological conditions
2. Doc 9976 (2015) Flight planning and performance manual (FPFM). Montreal: ICAO, First edition. ISBN 978-92-9249-838-2. p 63. p 4.14. Alternate aerodrome planning minima—establishing incremental values for ceiling and visibility. https://unitingaviation.com/livecycle/Documents/ICAO_Doc_9976-1_EN.pdf
3. Doc 10085 (2017) Extended Diversion Time Operations (EDTO) manual. Montreal: ICAO, first edition. ISBN 978-92-9258-327-9. p 74. 3.5.2.4 EDTO alternate aerodrome weather minima. https://www.icao.int/MID/Documents/2020/EDTO%20Workshop/10085_cons_en.pdf
4. FAA Advisory Circular AC120-42B (2008) «Extended Operations (ETOPS and Polar Operations)». U. S. Department of Transportation, Federal Aviation Administration. https://www.faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document.information/documentID/73587
5. EASA Acceptable Means of Compliance AMC20-6 (2010)«Extended range operation with two-engine aeroplanes ETOPS certification and operation». European Aviation Safety Agency. https://www.easa.europa.eu/sites/default/files/dfu/Annex%20II%20-%20AMC%2020-6.pdf